Crysis, DX10, 1680x1050 or higher, Very High, 8xAA? If you system can mince Crysis then you'll be doing 40+fps lol.
That just makes my point even better really, doesn't it? I don't actually know how it'll run on my current system because I've already played through and completed it. It could do 1000fps, it will make no difference to me just as the performance of GTAIV in 2 years time will make no difference to me.